Energy flow in a marine ecosystem

 

Energy flow in a marine ecosystem

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Energy flow in marine ecosystems

 

• Ecosystem includes living organisms (biotic community) and environment
• Solar energy converted to chemical energy by producers (mainly photosynthesis)
• Consumers eat other organisms
  • Herbivores
  • Carnivores
  • Omnivores
  • Bacteriovores
• Decomposers breaking down dead organisms or waste products

Algae-supported biotic community

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Nutrient flow in marine ecosystems

• Nutrients cycled from one chemical form to another
• Biogeochemical cycling
• Example, nutrients fixed by producers
• Passed onto consumers
• Some nutrients released to seawater through decomposers
• Nutrients can be recycled through upwelling

 

The aerobic desctruction of Organic Matter (OM)

• The Particulate Organic Matter (POM) in the ocean is composed of excreta, molts, dissoleve organic matter (DOM), living and dead tissues etc.
• The decomposition of this POM by bacteria, fungi, protozoans and animals can be represented as:

POM+Oxygen            CO2+Hydrogen+Ammonia+ Phosphoric acid (in soluble forms)

• This process is called nutrient regenaration or remineralization
  

 

The anaerobic destruction of OM

• There can be areas in the ocean with total or almost anaerobic condition persists
• In this case, ntitrate and sulfate can fuction as electron acceptors in the absence of oxygen, and thus enabling the oxidation of organic matter.
• POM+binitrate            carbon dioxide+water+Nitrogen+ammonium+phosphoric acid (refer to page 135 for chemical reaction)
• Similarly in case of sulphate ion, it releases sulphur in reduced form (sulphur ion)

Feeding strategies

 

• Suspension feeding or filter feeding
  • Take in seawater and filter out usable organic matter
• Deposit feeding
  • Take in detritus and sediment and extract usable organic matter
• Carnivorous feeding
  • Organisms capture and eat other animals

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Trophic levels

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Passage of energy between trophic levels

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Food chain         Food web

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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